Cobra push pull for aluminum

Discussion in 'Metal Boat Building' started by rocket, Oct 19, 2008.

  1. rocket
    Joined: Oct 2008
    Posts: 1
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    Location: Duncan

    rocket New Member

    To all that know, I have just purchased a cobra MK push pull gun for my lincoln welder off of ebay. I am running a lincoln power mig 255. Hoping all would be well I called a place in town, only to find that the cobra system will work only on the Lincoln 300 or 350 machine. He says that the machine will either feed to fast or too slow. The guy was quick to try and sell me the next model up of welder.

    My question is, has any of you played around with this type of thing or made adjustments that would allow this to work. Or, Do you weld with push pull for aluminum and use a suitcase?

    Thankyou in advance...oh, and this is my first post!

    I have always done it with fiberglass but have decided to make the change into aluminum fabrication.

    I have just sent away for plans to build my 25' Aluminum fishing machine and this is the welding system I have and would like to use.
  2. skypoke
    Joined: Dec 2002
    Posts: 41
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    skypoke Junior Member


    Can't comment on the 255, I bought a cobra setup along with a PM 300 and it was an awesome setup, zero problems. Built a 30' powercat, NZ design, cnc cut. I wouldn't think of trying to build in alloy without pulse welding and push pull.

  3. kmorin
    Joined: Apr 2005
    Posts: 185
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    Location: Alaska

    kmorin Senior Member

    Matching Torch/Feeder to Controls


    If you have issues with the MK product line, I'd suggest you contact the MK office directly. My reasoning is that MK is interested in supporting their products and Lincoln buys/bought the Cobramatic system from MK to put a reliable push pull into their wide variety of products. Lincoln isn't as interested in supporting MK as they are in their own countless products- its mainly a matter of size. MK is small and focused, Lincoln is huge and can't be as focused on someone else's 'buy-out' torch.

    If you try to put a Cobramatic onto a Lincoln power supply that doesn't have the internal wire spool as the mp 300 and 350 does, then you'd need a wire dispensing cabinet at the very least. Most of the wire cabinets provide a motor control and power supply. Not only does the motor in the wire cabinet need to be synchronized with the torch's wire feed motor but so does the drum brake and speed controls.

    I'm not positive I understood what your dilemma is, exactly, but my experience is that MK's tech people have helped me in the past when Lincoln's people were not responsive about gun issues.

    Please don't get me wrong about Lincoln's tech support- I've had discussions with welding engineers who KNEW their stuff, and called back and took time to educate me regarding their power supplies' features and capabilities. My remarks are directed to the Cobramatic torch assembly- its made by MK and they'd be more likely to have a ready answer and offer solutions.

    Things that I'd ask are:
    Does your 'new' cobra have a cabinet?
    Does the Lincoln power supply have a wire roll cabinet?
    Does the Cobramatic have the Lincoln cabinet adapter fittings on the hoses and cables?
    What are the voltages that your Lincoln provides to drive a wire feed motor- as compared to the voltages required by the model of Cobramatic torch/feeder you've acquired?

    I've owned Cobramatic(s) since the late '70's, still have three or four hanging around, but I use the MK Python on/in a Lincoln MP 350, now. The Cobras are all external wire housing and control systems with a cabinet and torch and the Lincoln has all of these integral to the power supply enclosure. I've powered the Cobras with Lincoln power supplies in the 70's then switched to the PowCon (first successful inverter machine) and even ran one Cobra on a Hobart Cyber TIG for a while when I was limited in power types in the old shop.

    You can combine almost any gun with almost any power supply if you are able to provide DC power supplies for the wire feed motor, a relay to turn on and off the main welding power and either a electric gas solenoid valve to control argon flow or a mechanical valve as in the older Cobra torch's handle.

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